Scala 2.10 : Install

 

Install Scala 2.10.

[1]. Make sure the current enabled version of Scala and Install it.

[root@dlp ~]# dnf module list scala

CentOS-8 - AppStream

Name  Stream   Profiles  Summary

scala 2.10 [d] common [d A hybrid functional/object-oriented language for the JV

               ]         M

Hint: [d]efault, [e]nabled, [x]disabled, [i]nstalled


# install Scala 2.10

[root@dlp ~]# dnf module -y install scala:2.10

[root@dlp ~]# scala -version

Scala code runner version 2.10.6 -- Copyright 2002-2013, LAMP/EPFL

[2]. Run Scala REPL (Read Eval Print Loop) which is the interactive shell to Test Scala.

[root@dlp ~]# scala

Welcome to Scala version 2.10.6 (OpenJDK 64-Bit Server VM, Java 1.8.0_232).

Type in expressions to have them evaluated.

Type :help for more information.


# print words

scala> println("Hello Scala World")

Hello Scala World


# set constants

scala> val msg:String = "Hello Scala World"

msg: String = Hello Scala World


scala> println(msg)

Hello Scala World


# exit

scala> sys.exit

[3]. Create a sample program to Test Scala.

[root@dlp ~]# vi readfile.scala

import java.io.File

import java.io.FileReader

import java.io.BufferedReader


object readfile {

  def main(args: Array[String]) {

    val reader = new BufferedReader(new FileReader(new File("/etc/passwd")))

    try {

      var line : String = null

        while ({ line = reader.readLine; line != null }) {

          println(line)

        }

    } finally {

      reader.close

    }

  }

}


# run as a script

[root@dlp ~]# scala readfile.scala

root:x:0:0:root:/root:/bin/bash

bin:x:1:1:bin:/bin:/sbin/nologin

daemon:x:2:2:daemon:/sbin:/sbin/nologin

adm:x:3:4:adm:/var/adm:/sbin/nologin

lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin

.....

.....


# compile and run

[root@dlp ~]# scalac readfile.scala

[root@dlp ~]# ll

total 16

-rw-------. 1 root root 1534 Oct 12 22:40  anaconda-ks.cfg

-rw-r--r--. 1 root root 1104 Dec 13 19:10 'readfile$.class'

-rw-r--r--. 1 root root  574 Dec 13 19:10  readfile.class

-rw-r--r--. 1 root root  387 Dec 13 19:10  readfile.scala


[root@dlp ~]# scala readfile

root:x:0:0:root:/root:/bin/bash

bin:x:1:1:bin:/bin:/sbin/nologin

daemon:x:2:2:daemon:/sbin:/sbin/nologin

adm:x:3:4:adm:/var/adm:/sbin/nologin

lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin

sync:x:5:0:sync:/sbin:/bin/sync

shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown

.....

.....


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